Neo-Queen Serenity (ネオ・クイーン・セレニティ Neo Kuīn Sereniti?) is the official title of Serena Tsukino in the 30th century. Some time in the future, Serena is appointed the Queen of Crystal Tokyo after saving the world from an evil spell that froze the planet.
Queen of Crystal Tokyo
When the earth is frozen over by an evil spell. Serena, and her husband, Darien Shields, were appointed to the position of royalty and became Neo-Queen Serenity and King Darien. Serenity used the power of the Imperium Silver Crystal to save the planet and its inhabitants. Tokyo was later renamed Crystal Tokyo.
Despite her maturity, Serenity maintained many of her spoiled and bratty traits, which she passed on to her daughter, Rini. However, whenever Rini would misbehave or over-rely on the people around her, Serenity and Darien attempted to teach her to stand on her own without help. Rini, unfortunately, internalized it as her parents being mean to her.
When several members of Planet Nemesis, exiled humans, attacked Crystal Tokyo, the defenses of the city were destroyed when Rini took the Silver Crystal from its pedestal. Serenity searched for her daughter during the chaos. When Serenity found her, she protected Rini from harm.
Rini, unaware she had inadvertently absorbed the crystal, repressed the memory of ever doing so. Afterward Serenity was placed in suspended animation when the Sailor Scouts trapped her inside a crystal quartz coffin for protection.
When Rini returns to the future with the past selves of Serenity, Darien and the Sailor Scouts, she is eventually able to save her mother and her home when she and Sailor Moon destroy the Wiseman, the orchestrator of their misfortune. Rini remained in the future and reunited with her mother, who expressed pride in her daughter's bravery.
However, feeling her daughter needed to be trained to become a Sailor Scout, Serenity sends Rini back to the 20th century.